Sounds ridiculous. The rules state:
If there was NOT a combat in the sea zone from which you
are offloading units from transports, any accompanying
battleships and cruisers in that sea zone can conduct a one-time
bombardment of one coastal territory or island group being
attacked. The number of ships that can make bombardment
attacks is limited to 1 ship per land unit being offloaded
from the transports in that coastal territory. If more than one
territory is being assaulted from the same sea zone and there
are multiple battleships and/or cruisers, each ship may support
only one assault. However, the ships’ bombardment may
be split in any way that the attacker chooses, so long as the
number of ships supporting each assault doesn’t exceed the
number of seaborne land units in that assault. Choosing to
destroy enemy transports or attacking enemy submarines in
step 1 (above), counts as a combat and prevents the battleship
and cruiser bombardment from taking place.
It also opens a loophole that a battleship can conduct sea combat in zone 113 then bombard West Germany if an infantry is unloaded from zone 112.